The invention concerns a method for automatically controlling an internal combustion engine, in which an axial displacement and an angle of rotation of the gas-exchange valve are continuously measured.
In practice, large diesel engines are delivered without automatic valve clearance compensation. Therefore, after a rigidly prescribed operating time, the valve clearance must be adjusted by a service mechanic in accordance with a maintenance schedule. The boundary conditions, for example, cooling water temperature less than 40° C., and the individual steps are described in the maintenance schedule. First, a hand crank is applied, the cylinder head cover is removed, and the gas-exchange valves are sequentially brought into the closed state by the hand crank. In the closed state, the given actual valve clearance is then measured by a thickness gage. If it deviates from the desired valve clearance, the service mechanic must adjust the actual valve clearance by an adjusting screw until it conforms to the desired valve clearance. In a large diesel engine unit with, for example, sixteen cylinders, this is complicated and cost-intensive and, in the case of a ship, results in greater harbor dues.
To avoid deposits on a gas-exchange valve, it is well known that the gas-exchange valve can be turned by an angle. A rotating device is described, for example, in DE 196 47 412 C1. It is also well known to measure the turning of the gas-exchange valve and to use this measurement to evaluate operability. For example, DE 94 17 650 U1 describes a measuring device of this type, in which a permanent magnet is arranged on the rotating device, and the measuring sensor is arranged in the cylinder head. An unsatisfactory valve rotating device is then to be exchanged.